Laser welding under vacuum exhibits wonderful application prospects in thick plates welding from shipbuilding, nuclear instrument and pressure vessel industries. The review of this issue summarizes the related research results of vacuum laser welding technology at home and abroad, analyzes the problems in the technology. Influences of ambient pressure on the laser welding penetration depth, surface formation and porosity defect are presented based on domestic and global development. High power fiber lasers are widely used in laser welding and cutting areas. A high power single-mode Yb-doped fiber laser employing 976nm pump has been demonstrated in this issue, which show good performance in laser beam quality and stability. The research articles present both high-power, 976-nm single-mode doped Yb fiber lasers and the design of spectacle-optical lens systems. In addition, one article also introduced a sub-wavelength surface plasmon optical waveguide structure.